Page 58 - 2016Winter

TECHNICAL COMMITTEE REPORT
Nathan McDannold
Postal:
Department of Radiology Brigham and Women's Hospital 221 Longwood Avenue, Room 521 Boston, Massachusetts 02130 USA
Email:
njm@bwh.harvard.edu
Biomedical Acoustics
The Technical Committee (TC) on Biomedical Acoustics (BA), one of the most diverse groups in the Acoustical Society of America (ASA), is composed of indi- viduals whose interests cover a broad range of diagnostic and therapeutic applica- tions or, more generally, the interaction of sound with biological materials. BA was formerly known as Biomedical Ultrasound/Bioresponse to Vibration. The BATC is concerned with the study of the interactions of acoustic waves with biological materials, including cells, tissues, organ systems, and entire organisms.
The areas of interest of members of the BATC include the diagnostic and thera- peutic applications of acoustics in medicine, the biological effects of exposure to mechanical vibration and acoustic waves, acoustic propagation in biological ma- terials, instrumentation, ultrasound field calibration, exposimetry and dosimetry, ultrasound contrast agents, medical image and signal processing, the characteriza- tion and processing of biological materials, ultrasonic characterization of bones, and acoustic-based physiological measurements. Acoustics-based imaging meth- ods and therapies have potential applications, many of them only emerging in the last decade, that touch every conceivable medical condition, and it would be im- possible to review all of them.
Topics discussed during BATC sessions include nonlinear acoustic propagation through different tissue structures, the design of phased-array transducers and driving electronics, the use of MRI to measure temperature during ultrasonic sur- gery, the use of lasers to generate acoustic waves, the delivery of genes or stem cells to the brain or heart, and the use of focused ultrasound to push around kid- ney stones. These diverse topics reflect the multidisciplinary makeup of the scien- tists and students who work in this area. Although the BATC is not the largest TC within the ASA and the associated areas of research are often represented in many other conferences, it remains a community for researchers who are interested in technically rigorous explorations of the application of acoustics in medicine. This core of acousticians makes the ASA a unique venue for scientists, students, and others who are interested in learning not only the newest applications but also the detailed acoustical principles that govern them. This aspect is sometimes missing in other conferences.
Imaging is one of the major general areas that is encountered at the BATC. Al- though ultrasound imaging has been a medical staple for decades, it is still a very active area of research and there are a growing number of different approaches that are advancing rapidly. One example is photoacoustics, where laser pulses are applied into the tissue and the resulting thermal expansion creates an acoustic wave that can be detected using a transducer or transducer array (Wang and Yao, 2016). Thus one can produce images using optical contrast with ultrasound, with the ability to penetrate deeper into the tissue than other approaches. This field has advanced greatly in recent years and is often represented in BATC sessions at ASA conferences. The use of acoustics to probe tissue elasticity is also an active area of research (Garra, 2015). Through cross-correlation of speckle patterns, one can measure minute displacements in the tissue produced by an external force. Re- cently, ultrafast ultrasound imaging has been employed to map shear waves in tis-
56 | Acoustics Today | Winter 2016 | volume 12, issue 4 ©2016 Acoustical Society of America. All rights reserved.